699
FXUS65 KTWC 291534
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
834 AM MST Sun Jun 29 2025

.SYNOPSIS...Hot temperatures continue in the near term with high
temperatures peaking on Monday when an Extreme Heat Warning is in
effect for portions of southeast Arizona. Monsoon moisture will
increase this week with the main threats Monday and Tuesday being
gusty winds and blowing dust, then transitioning to a heavy rain and
flash flood threat Wednesday and Thursday. While shower and
thunderstorm chances continue Independence Day and the weekend,
coverage is expected to decrease. Temperatures will drop to near
normal levels Wednesday, then below normal to end the week.

&&

.UPDATE... Lingering clouds from overnight continue to dissipate
this morning. High pressure is centered over the central Arizona/
New Mexico line leading to above normal high temperatures around
105-110 degrees today and Moderate to Minor HeatRisk. Enough
moisture will push into eastern Cochise and Greenlee counties this
afternoon to have slight chances (10 to 15%) for showers and
storms to develop, otherwise dry conditions are expected today.
Storms that form this afternoon will likely produce light to
moderate rainfall and may lead to some gusty winds that could pick
up some dust. In general, expect any storms and showers that
develop to be sub-severe today.

&&

.PREV DISCUSSION... /issued 241 AM MST Sun Jun 29 2025/

.KEY MESSAGES...

-Temperatures peak Monday with highs of 108 to 114 degrees in the
deserts including Tucson and Upper Gila River Valley. An Extreme
Heat Warning is in effect Monday for these locales.

-Generally dry conditions today with only a 10% chance of showers
and thunderstorms mainly in the Douglas area and SE Cochise County.

-Monsoon 2025 will swing into full gear this week. The heat will be
on the downward trend by midweek as moisture will be on the
increase. Isolated to scattered showers and thunderstorms mainly
east of Tucson Monday, then from Sells eastward Tuesday. Main
threats Monday and Tuesday focused on gusty winds and blowing dust,
then transition more towards heavy rain and flash flooding threats
Wednesday through Thursday. Shower and thunderstorm chances continue
Independence Day and next weekend but less coverage compared to
Wednesday and Thursday.

&&

.DISCUSSION...Clear skies across southeast Arizona this morning.
High pressure aloft will result in hotter temperatures today and
Monday, with highs peaking on Monday before a downward trend in
temperatures thereafter. The forecast high in Tucson is 111 degrees
on Monday and this is just below the daily record of 112 (1989). An
Extreme Heat Warning remains in effect Monday for Pima, SE Pinal and
the Upper Gila Valley region of Graham County.

The main forecast challenge this week will be the transition and
then full onset into a monsoonal pattern. While recent activity has
been limited in scope to near the NM border that is going to change
this week. However, in the short term, we`re still looking at a ~10%
chance of showers and thunderstorms in SE Cochise County today,
mainly around the Douglas area. Just like we`ve seen over the past
few days, any shower or thunderstorm activity (or outflow from NM)
will be capable of producing a few spots of blowing dust in far
eastern Cochise County.

The transition will start to become a bit more pronounced on Monday.
Even though heights peak on Monday, the high is already starting to
shift just to our northeast allowing a bit more of a mid level
easterly steering flow. This will help to import a bit more moisture
especially across Cochise/Graham/Greenlee Counties. With PWAT`s
around 1 inch and hot surface temperatures with deep layer mixing to
around 550mb, the isolated to scattered shower and thunderstorms
that do develop will result in gusty outflow winds and localized
blowing dust. The 00Z HREF 40km neighborhood probabilities show a
70%+ chance of wind gusts greater than 30kts across
Graham/Greenlee/Cochise Counties by late afternoon Monday and a 10-
30% chance of 50kts. Isolated storms may occur as far west as the
Tucson area late Monday afternoon and early evening where these
greater than 30kt probabilities are closer to 50%. Any rainfall in
this environment will be quite limited. A more pronounced moisture
increase is expected Monday night to spread westward through most of
our forecast area from New Mexico and Chihuahua.

Tuesday will likely be the day that most folks feel the monsoonal
moisture as surface dewpoints Tuesday morning jump into the 50s for
most of the forecast area with corresponding PWAT values 1 to 1.25
inches. As the high aloft weakens Tuesday and with increased
moisture levels, scattered showers and thunderstorms will develop
midday into the afternoon hours from the T.O. nation eastward.
Tuesday will still see pretty typical early season storm threats due
to continued strong surface heating/inverted-v profile resulting in
strong outflow winds with storm activity along with blowing dust in
typically prone areas.

Even deeper moisture will move in for Wednesday and Thursday, coming
up from Sonora and the Gulf of California assisted by an anticipated
tropical cyclone moving up close to the southern Baja by Thursday.
This increased moisture with PWATs jumping to around 1.3-1.6 inches
for most of the forecast area (130-180% of normal) will result in
the transition of shower and thunderstorm activity more towards
areas of heavy rain with localized flash flooding potential. Still
uncertainty on the exact details but this kind of pattern does have
the potential to lose a bit of the typical diurnal pattern we
usually see with thunderstorm activity as a weak trough to our west
may also aid in lift.

For Independence Day and into the weekend, latest runs in the
ensembles showing some modest drying as west to southwest flow aloft
returns. If these trends hold up, shower and thunderstorm coverage
will be less compared to Wednesday and Thursday, and more focused on
locales south and east of Tucson with the NBM overdone on PoPs.

&&

.AVIATION...Valid through 30/12Z. SKC this morning, with
SCT-BKN clouds AOA 10-13k ft AGL again aft 29/19Z mainly south and
east of KTUS including KDUG and KOLS. There is a slight chc of isold
-SHRA/-TSRA for KDUG 29/19Z-30/03Z but otherwise dry conditions for
other terminals. Isold gusts up to 30-40 kts near any -SHRA/-TSRA,
otherwise sfc winds NWLY at 8-12 kts this afternoon and less than 10
kts otherwise. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Warmer temperatures and generally dry conditions
today with isolated showers and thunderstorms this weekend will
mainly be confined along the International Border in Cochise County.
Minimum relative humidities from 10 to 20 percent through Monday,
then increasing to 15 to 30 percent Tuesday and Wednesday and 25 to
50 percent Thursday and Friday. Winds generally light and under 15
mph with isolated gusts up to 45 mph under any thunderstorms.
Moisture will be on the increase this week with typical early
monsoon season threats of gusty winds and lightning with lack of
wetting rains through Monday and Tuesday. However, widespread rain
chances due to additional moisture move in Wednesday and Thursday
with the threats transitioning to heavy rain and flash flooding.

&&

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning from 10 AM to 8 PM MST Monday for AZZ501-
502-504>506-509.

&&

$$

Malarkey/ Lader

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